1 3359 128 HISTONE H4 LYSINE 16 ACETYLATION CONTROLS CENTRAL CARBON METABOLISM AND DIET-INDUCED OBESITY IN MICE. NONCOMMUNICABLE DISEASES (NCDS) ACCOUNT FOR OVER 70% OF DEATHS WORLD-WIDE. PREVIOUS WORK HAS LINKED NCDS SUCH AS TYPE 2 DIABETES (T2D) TO DISRUPTION OF CHROMATIN REGULATORS. HOWEVER, THE EXACT MOLECULAR ORIGINS OF THESE CHRONIC CONDITIONS REMAIN ELUSIVE. HERE, WE IDENTIFY THE H4 LYSINE 16 ACETYLTRANSFERASE MOF AS A CRITICAL REGULATOR OF CENTRAL CARBON METABOLISM. HIGH-THROUGHPUT METABOLOMICS UNVEIL A SYSTEMIC AMINO ACID AND CARBOHYDRATE IMBALANCE IN MOF DEFICIENT MICE, MANIFESTING IN T2D PREDISPOSITION. ORAL GLUCOSE TOLERANCE TESTING (OGTT) REVEALS DEFECTS IN GLUCOSE ASSIMILATION AND INSULIN SECRETION IN THESE ANIMALS. FURTHERMORE, MOF DEFICIENT MICE ARE RESISTANT TO DIET-INDUCED FAT GAIN DUE TO DEFECTS IN GLUCOSE UPTAKE IN ADIPOSE TISSUE. MOF-MEDIATED H4K16AC DEPOSITION CONTROLS EXPRESSION OF THE MASTER REGULATOR OF GLUCOSE METABOLISM, PPARG AND THE ENTIRE DOWNSTREAM TRANSCRIPTIONAL NETWORK. GLUCOSE UPTAKE AND LIPID STORAGE CAN BE RECONSTITUTED IN MOF-DEPLETED ADIPOCYTES IN VITRO BY ECTOPIC GLUT4 EXPRESSION, PPARGAMMA AGONIST THIAZOLIDINEDIONE (TZD) TREATMENT OR SIRT1 INHIBITION. HENCE, CHRONIC IMBALANCE IN H4K16AC PROMOTES A DESTABILISATION OF METABOLISM TRIGGERING THE DEVELOPMENT OF A METABOLIC DISORDER, AND ITS MAINTENANCE PROVIDES AN UNPRECEDENTED REGULATORY EPIGENETIC MECHANISM CONTROLLING DIET-INDUCED OBESITY. 2021 2 6471 34 TNF-ALPHA REGULATES DIABETIC MACROPHAGE FUNCTION THROUGH THE HISTONE ACETYLTRANSFERASE MOF. A CRITICAL COMPONENT OF WOUND HEALING IS THE TRANSITION FROM THE INFLAMMATORY PHASE TO THE PROLIFERATION PHASE TO INITIATE HEALING AND REMODELING OF THE WOUND. MACROPHAGES ARE CRITICAL FOR THE INITIATION AND RESOLUTION OF THE INFLAMMATORY PHASE DURING WOUND REPAIR. IN DIABETES, MACROPHAGES DISPLAY A SUSTAINED INFLAMMATORY PHENOTYPE IN LATE WOUND HEALING CHARACTERIZED BY ELEVATED PRODUCTION OF INFLAMMATORY CYTOKINES, SUCH AS TNF-ALPHA. PREVIOUS STUDIES HAVE SHOWN THAT AN ALTERED EPIGENETIC PROGRAM DIRECTS DIABETIC MACROPHAGES TOWARD A PROINFLAMMATORY PHENOTYPE, CONTRIBUTING TO A SUSTAINED INFLAMMATORY PHASE. MALES ABSENT ON THE FIRST (MOF) IS A HISTONE ACETYLTRANSFERASE (HAT) THAT HAS BEEN SHOWN BE A COACTIVATOR OF TNF-ALPHA SIGNALING AND PROMOTE NF-KAPPAB-MEDIATED GENE TRANSCRIPTION IN PROSTATE CANCER CELL LINES. BASED ON MOF'S ROLE IN TNF-ALPHA/NF-KAPPAB-MEDIATED GENE EXPRESSION, WE HYPOTHESIZED THAT MOF INFLUENCES MACROPHAGE-MEDIATED INFLAMMATION DURING WOUND REPAIR. WE USED MYELOID-SPECIFIC MOF-KNOCKOUT (LYZ2CRE MOFFL/FL) AND DIET-INDUCED OBESE (DIO) MICE TO DETERMINE THE FUNCTION OF MOF IN DIABETIC WOUND HEALING. MOF-DEFICIENT MICE EXHIBITED REDUCED INFLAMMATORY CYTOKINE GENE EXPRESSION. FURTHERMORE, WE FOUND THAT WOUND MACROPHAGES FROM DIO MICE HAD ELEVATED MOF LEVELS AND HIGHER LEVELS OF ACETYLATED HISTONE H4K16, MOF'S PRIMARY SUBSTRATE OF HAT ACTIVITY, ON THE PROMOTERS OF INFLAMMATORY GENES. WE FURTHER IDENTIFIED THAT MOF EXPRESSION COULD BE STIMULATED BY TNF-ALPHA AND THAT TREATMENT WITH ETANERCEPT, AN FDA-APPROVED TNF-ALPHA INHIBITOR, REDUCED MOF LEVELS AND IMPROVED WOUND HEALING IN DIO MICE. THIS REPORT IS THE FIRST TO OUR KNOWLEDGE TO DEFINE AN IMPORTANT ROLE FOR MOF IN REGULATING MACROPHAGE-MEDIATED INFLAMMATION IN WOUND REPAIR AND IDENTIFIES TNF-ALPHA INHIBITION AS A POTENTIAL THERAPY FOR THE TREATMENT OF CHRONIC INFLAMMATION IN DIABETIC WOUNDS. 2020 3 2181 26 EPIGENETIC MECHANISMS REGULATE NADPH OXIDASE-4 EXPRESSION IN CELLULAR SENESCENCE. AGING IS A WELL-KNOWN RISK FACTOR FOR A LARGE NUMBER OF CHRONIC DISEASES, INCLUDING THOSE OF THE LUNG. CELLULAR SENESCENCE IS ONE OF THE HALLMARKS OF AGING, AND CONTRIBUTES TO THE PATHOGENESIS OF AGE-RELATED DISEASES. RECENT STUDIES IMPLICATE THE REACTIVE OXYGEN SPECIES (ROS)-GENERATING ENZYME, NADPH OXIDASE 4 (NOX4) IN CELLULAR SENESCENCE. IN THIS STUDY, WE INVESTIGATED POTENTIAL MECHANISMS FOR EPIGENETIC REGULATION OF NOX4. WE OBSERVED CONSTITUTIVELY HIGH LEVELS OF NOX4 GENE/PROTEIN AND ACTIVITY IN A MODEL OF REPLICATION-INDUCED CELLULAR SENESCENCE OF LUNG FIBROBLASTS. IN REPLICATIVE SENESCENT FIBROBLASTS, THE NOX4 GENE IS ENRICHED WITH THE ACTIVATION HISTONE MARK, H4K16AC, AND INVERSELY ASSOCIATED WITH THE REPRESSIVE HISTONE MARK, H4K20ME3, SUPPORTING AN ACTIVE TRANSCRIPTIONAL CHROMATIN CONFORMATION. SILENCING OF THE HISTONE ACETYLTRANSFERASE MOF, WHICH SPECIFICALLY ACETYLATES H4K16, DOWN-REGULATES NOX4 GENE/PROTEIN EXPRESSION. THE NOX4 GENE PROMOTER IS RICH IN CPG SITES; MIXED COPIES OF METHYLATED AND UNMETHYLATED NOX4 DNA WERE DETECTED IN BOTH NONSENESCENT AND SENESCENT CELLS. INTERESTINGLY, THE NOX4 GENE IS VARIABLY ASSOCIATED WITH SPECIFIC DNA METHYLTRANSFERASES AND METHYL BINDING PROTEINS IN THESE TWO CELL POPULATIONS. THESE RESULTS INDICATE A CRITICAL ROLE FOR HISTONE MODIFICATIONS INVOLVING H4K16AC IN EPIGENETIC ACTIVATION OF THE NOX4 GENE, WHILE THE ROLE OF DNA METHYLATION MAY BE CONTEXTUAL. DEFINING MECHANISMS FOR THE EPIGENETIC REGULATION OF NOX4 WILL AID IN THE DEVELOPMENT OF NOVEL THERAPEUTIC STRATEGIES FOR AGE-RELATED DISEASES IN WHICH THIS GENE IS OVEREXPRESSED, IN PARTICULAR IDIOPATHIC PULMONARY FIBROSIS AND CANCER. 2015 4 4506 25 MRTF-A MEDIATES LPS-INDUCED PRO-INFLAMMATORY TRANSCRIPTION BY INTERACTING WITH THE COMPASS COMPLEX. CHRONIC INFLAMMATION UNDERSCORES THE PATHOGENESIS OF A RANGE OF HUMAN DISEASES. LIPOPOLYSACCHARIDE (LPS) ELICITS STRONG PRO-INFLAMMATORY RESPONSES IN MACROPHAGES THROUGH THE TRANSCRIPTION FACTOR NF-KAPPAB. THE EPIGENETIC MECHANISM UNDERLYING LPS-INDUCED PRO-INFLAMMATORY TRANSCRIPTION IS NOT FULLY UNDERSTOOD. HEREIN, WE DESCRIBE A ROLE FOR MYOCARDIN-RELATED TRANSCRIPTION FACTOR A (MRTF-A, ALSO KNOWN AS MKL1) IN THIS PROCESS. MRTF-A OVEREXPRESSION ENHANCED NF-KAPPAB-DEPENDENT PRO-INFLAMMATORY TRANSCRIPTION, WHEREAS MRTF-A SILENCING INHIBITED THIS PROCESS. MRTF-A DEFICIENCY ALSO REDUCED THE SYNTHESIS OF PRO-INFLAMMATORY MEDIATORS IN A MOUSE MODEL OF COLITIS. LPS PROMOTED THE RECRUITMENT OF MRTF-A TO THE PROMOTERS OF PRO-INFLAMMATORY GENES IN AN NF-KAPPAB-DEPENDENT MANNER. RECIPROCALLY, MRTF-A INFLUENCED THE NUCLEAR ENRICHMENT AND TARGET BINDING OF NF-KAPPAB. MECHANISTICALLY, MRTF-A WAS NECESSARY FOR THE ACCUMULATION OF ACTIVE HISTONE MODIFICATIONS ON NF-KAPPAB TARGET PROMOTERS BY COMMUNICATING WITH THE HISTONE H3K4 METHYLTRANSFERASE COMPLEX (COMPASS). SILENCING OF INDIVIDUAL MEMBERS OF COMPASS, INCLUDING ASH2, WDR5 AND SET1 (ALSO KNOWN AS SETD1A), DOWNREGULATED THE PRODUCTION OF PRO-INFLAMMATORY MEDIATORS AND IMPAIRED THE NF-KAPPAB KINETICS. IN SUMMARY, OUR WORK HAS UNCOVERED A PREVIOUSLY UNKNOWN FUNCTION FOR MRTF-A AND PROVIDED INSIGHTS INTO THE RATIONALIZED DEVELOPMENT OF ANTI-INFLAMMATORY THERAPEUTIC STRATEGIES. 2014 5 192 31 ACETYLATED H4K16 BY MYST1 PROTECTS UROTSA CELLS FROM ARSENIC TOXICITY AND IS DECREASED FOLLOWING CHRONIC ARSENIC EXPOSURE. ARSENIC, A HUMAN CARCINOGEN THAT IS ASSOCIATED WITH AN INCREASED RISK OF BLADDER CANCER, IS COMMONLY FOUND IN DRINKING WATER. AN IMPORTANT MECHANISM BY WHICH ARSENIC IS THOUGHT TO BE CARCINOGENIC IS THROUGH THE INDUCTION OF EPIGENETIC CHANGES THAT LEAD TO ABERRANT GENE EXPRESSION. PREVIOUSLY, WE REPORTED THAT THE SAS2 GENE IS REQUIRED FOR OPTIMAL GROWTH OF YEAST IN THE PRESENCE OF ARSENITE (AS(III)). YEAST SAS2P IS ORTHOLOGOUS TO HUMAN MYST1, A HISTONE 4 LYSINE 16 (H4K16) ACETYLTRANSFERASE. HERE, WE SHOW THAT H4K16 ACETYLATION IS NECESSARY FOR THE RESISTANCE OF YEAST TO AS(III) THROUGH THE MODULATION OF CHROMATIN STATE. WE FURTHER EXPLORED THE ROLE OF MYST1 AND H4K16 ACETYLATION IN ARSENIC TOXICITY AND CARCINOGENESIS IN HUMAN BLADDER EPITHELIAL CELLS. THE EXPRESSION OF MYST1 WAS KNOCKED DOWN IN UROTSA CELLS, A MODEL OF BLADDER EPITHELIUM THAT HAS BEEN USED TO STUDY ARSENIC-INDUCED CARCINOGENESIS. SILENCING OF MYST1 REDUCED ACETYLATION OF H4K16 AND INDUCED SENSITIVITY TO AS(III) AND TO ITS MORE TOXIC METABOLITE MONOMETHYLARSONOUS ACID (MMA(III)) AT DOSES RELEVANT TO HIGH ENVIRONMENTAL HUMAN EXPOSURES. IN ADDITION, BOTH AS(III) AND MMA(III) TREATMENTS DECREASED GLOBAL H4K16 ACETYLATION LEVELS IN A DOSE- AND TIME-DEPENDENT MANNER. THIS INDICATES THAT ACETYLATED H4K16 IS REQUIRED FOR RESISTANCE TO ARSENIC AND THAT A REDUCTION IN ITS LEVELS AS A CONSEQUENCE OF ARSENIC EXPOSURE MAY CONTRIBUTE TO TOXICITY IN UROTSA CELLS. BASED ON THESE FINDINGS, WE PROPOSE A NOVEL ROLE FOR THE MYST1 GENE IN HUMAN SENSITIVITY TO ARSENIC. 2009 6 1945 27 EPIGALLOCATECHIN-3-GALLATE, A HISTONE ACETYLTRANSFERASE INHIBITOR, INHIBITS EBV-INDUCED B LYMPHOCYTE TRANSFORMATION VIA SUPPRESSION OF RELA ACETYLATION. BECAUSE THE P300/CBP-MEDIATED HYPERACETYLATION OF RELA (P65) IS CRITICAL FOR NUCLEAR FACTOR-KAPPAB (NF-KAPPAB) ACTIVATION, THE ATTENUATION OF P65 ACETYLATION IS A POTENTIAL MOLECULAR TARGET FOR THE PREVENTION OF CHRONIC INFLAMMATION. DURING OUR ONGOING SCREENING STUDY TO IDENTIFY NATURAL COMPOUNDS WITH HISTONE ACETYLTRANSFERASE INHIBITOR (HATI) ACTIVITY, WE IDENTIFIED EPIGALLOCATECHIN-3-GALLATE (EGCG) AS A NOVEL HATI WITH GLOBAL SPECIFICITY FOR THE MAJORITY OF HAT ENZYMES BUT WITH NO ACTIVITY TOWARD EPIGENETIC ENZYMES INCLUDING HDAC, SIRT1, AND HMTASE. AT A DOSE OF 100 MICROMOL/L, EGCG ABROGATES P300-INDUCED P65 ACETYLATION IN VITRO AND IN VIVO, INCREASES THE LEVEL OF CYTOSOLIC IKAPPABALPHA, AND SUPPRESSES TUMOR NECROSIS FACTOR ALPHA (TNFALPHA)-INDUCED NF-KAPPAB ACTIVATION. WE ALSO SHOWED THAT EGCG PREVENTS TNFALPHA-INDUCED P65 TRANSLOCATION TO THE NUCLEUS, CONFIRMING THAT HYPERACETYLATION IS CRITICAL FOR NF-KAPPAB TRANSLOCATION AS WELL AS ACTIVITY. FURTHERMORE, EGCG TREATMENT INHIBITED THE ACETYLATION OF P65 AND THE EXPRESSION OF NF-KAPPAB TARGET GENES IN RESPONSE TO DIVERSE STIMULI. FINALLY, EGCG REDUCED THE BINDING OF P300 TO THE PROMOTER REGION OF INTERLEUKIN-6 GENE WITH AN INCREASED RECRUITMENT OF HDAC3, WHICH HIGHLIGHTS THE IMPORTANCE OF THE BALANCE BETWEEN HATS AND HISTONE DEACETYLASES IN THE NF-KAPPAB-MEDIATED INFLAMMATORY SIGNALING PATHWAY. IMPORTANTLY, EGCG AT 50 MICROMOL/L DOSE COMPLETELY BLOCKS EBV INFECTION-INDUCED CYTOKINE EXPRESSION AND SUBSEQUENTLY THE EBV-INDUCED B LYMPHOCYTE TRANSFORMATION. THESE RESULTS SHOW THE CRUCIAL ROLE OF ACETYLATION IN THE DEVELOPMENT OF INFLAMMATORY-RELATED DISEASES. 2009 7 5993 28 TGFBETA PROMOTES FIBROSIS BY MYST1-DEPENDENT EPIGENETIC REGULATION OF AUTOPHAGY. ACTIVATION OF FIBROBLASTS IS ESSENTIAL FOR PHYSIOLOGICAL TISSUE REPAIR. UNCONTROLLED ACTIVATION OF FIBROBLASTS, HOWEVER, MAY LEAD TO TISSUE FIBROSIS WITH ORGAN DYSFUNCTION. ALTHOUGH SEVERAL PATHWAYS CAPABLE OF PROMOTING FIBROBLAST ACTIVATION AND TISSUE REPAIR HAVE BEEN IDENTIFIED, THEIR INTERPLAY IN THE CONTEXT OF CHRONIC FIBROTIC DISEASES REMAINS INCOMPLETELY UNDERSTOOD. HERE, WE PROVIDE EVIDENCE THAT TRANSFORMING GROWTH FACTOR-BETA (TGFBETA) ACTIVATES AUTOPHAGY BY AN EPIGENETIC MECHANISM TO AMPLIFY ITS PROFIBROTIC EFFECTS. TGFBETA INDUCES AUTOPHAGY IN FIBROTIC DISEASES BY SMAD3-DEPENDENT DOWNREGULATION OF THE H4K16 HISTONE ACETYLTRANSFERASE MYST1, WHICH REGULATES THE EXPRESSION OF CORE COMPONENTS OF THE AUTOPHAGY MACHINERY SUCH AS ATG7 AND BECLIN1. ACTIVATION OF AUTOPHAGY IN FIBROBLASTS PROMOTES COLLAGEN RELEASE AND IS BOTH, SUFFICIENT AND REQUIRED, TO INDUCE TISSUE FIBROSIS. FORCED EXPRESSION OF MYST1 ABROGATES THE STIMULATORY EFFECTS OF TGFBETA ON AUTOPHAGY AND RE-ESTABLISHES THE EPIGENETIC CONTROL OF AUTOPHAGY IN FIBROTIC CONDITIONS. INTERFERENCE WITH THE ABERRANT ACTIVATION OF AUTOPHAGY INHIBITS TGFBETA-INDUCED FIBROBLAST ACTIVATION AND AMELIORATES EXPERIMENTAL DERMAL AND PULMONARY FIBROSIS. THESE FINDINGS LINK UNCONTROLLED TGFBETA SIGNALING TO ABERRANT AUTOPHAGY AND DEREGULATED EPIGENETICS IN FIBROTIC DISEASES AND MAY CONTRIBUTE TO THE DEVELOPMENT OF THERAPEUTIC INTERVENTIONS IN FIBROTIC DISEASES. 2021 8 3656 29 INDUCIBLE PRMT1 ABLATION IN ADULT VASCULAR SMOOTH MUSCLE LEADS TO CONTRACTILE DYSFUNCTION AND AORTIC DISSECTION. VASCULAR SMOOTH MUSCLE CELLS (VSMCS) HAVE REMARKABLE PLASTICITY IN RESPONSE TO DIVERSE ENVIRONMENTAL CUES. ALTHOUGH THESE CELLS ARE VERSATILE, CHRONIC STRESS CAN TRIGGER VSMC DYSFUNCTION, WHICH ULTIMATELY LEADS TO VASCULAR DISEASES SUCH AS AORTIC ANEURYSM AND ATHEROSCLEROSIS. PROTEIN ARGININE METHYLTRANSFERASE 1 (PRMT1) IS A MAJOR ENZYME CATALYZING ASYMMETRIC ARGININE DIMETHYLATION OF PROTEINS THAT ARE SOURCES OF ASYMMETRIC DIMETHYLARGININE (ADMA), AN ENDOGENOUS INHIBITOR OF NITRIC OXIDE SYNTHASE. ALTHOUGH A POTENTIAL ROLE OF PRMT1 IN VASCULAR PATHOGENESIS HAS BEEN PROPOSED, ITS ROLE IN VASCULAR FUNCTION HAS YET TO BE CLARIFIED. HERE, WE INVESTIGATED THE ROLE AND UNDERLYING MECHANISM OF PRMT1 IN VASCULAR SMOOTH MUSCLE CONTRACTILITY AND FUNCTION. THE EXPRESSION OF PRMT1 AND CONTRACTILE-RELATED GENES WAS SIGNIFICANTLY DECREASED IN THE AORTAS OF ELDERLY HUMANS AND PATIENTS WITH AORTIC ANEURYSMS. MICE WITH VSMC-SPECIFIC PRMT1 ABLATION (SMKO) EXHIBITED PARTIAL LETHALITY, LOW BLOOD PRESSURE AND AORTIC DILATION. THE PRMT1-ABLATED AORTAS SHOWED AORTIC DISSECTION WITH ELASTIC FIBER DEGENERATION AND CELL DEATH. EX VIVO AND IN VITRO ANALYSES INDICATED THAT PRMT1 ABLATION SIGNIFICANTLY DECREASED THE CONTRACTILITY OF THE AORTA AND TRACTION FORCES OF VSMCS. PRMT1 ABLATION DOWNREGULATED THE EXPRESSION OF CONTRACTILE GENES SUCH AS MYOCARDIN WHILE UPREGULATING THE EXPRESSION OF SYNTHETIC GENES, THUS CAUSING THE CONTRACTILE TO SYNTHETIC PHENOTYPIC SWITCH OF VSMCS. IN ADDITION, MECHANISTIC STUDIES DEMONSTRATED THAT PRMT1 DIRECTLY REGULATES MYOCARDIN GENE ACTIVATION BY MODULATING EPIGENETIC HISTONE MODIFICATIONS IN THE MYOCARDIN PROMOTER REGION. THUS, OUR STUDY DEMONSTRATES THAT VSMC PRMT1 IS ESSENTIAL FOR VASCULAR HOMEOSTASIS AND THAT ITS ABLATION CAUSES AORTIC DILATION/DISSECTION THROUGH IMPAIRED MYOCARDIN EXPRESSION. 2021 9 4574 27 MYOCARDIN-RELATED TRANSCRIPTION FACTOR A EPIGENETICALLY REGULATES RENAL FIBROSIS IN DIABETIC NEPHROPATHY. DIABETIC NEPHROPATHY (DN) IS ONE OF THE MOST COMMON COMPLICATIONS ASSOCIATED WITH DIABETES AND CHARACTERIZED BY RENAL MICROVASCULAR INJURY ALONG WITH ACCELERATED SYNTHESIS OF EXTRACELLULAR MATRIX PROTEINS CAUSING TUBULOINTERSTITIAL FIBROSIS. PRODUCTION OF TYPE I COLLAGEN, THE MAJOR COMPONENT OF EXTRACELLULAR MATRIX, IS AUGMENTED DURING RENAL FIBROSIS AFTER CHRONIC EXPOSURE TO HYPERGLYCEMIA. HOWEVER, THE TRANSCRIPTIONAL MODULATOR RESPONSIBLE FOR THE EPIGENETIC MANIPULATION LEADING TO INDUCTION OF TYPE I COLLAGEN GENES IS NOT CLEARLY DEFINED. WE SHOW HERE THAT TUBULOINTERSTITIAL FIBROSIS AS A RESULT OF DN WAS DIMINISHED IN MYOCARDIN-RELATED TRANSCRIPTION FACTOR A (MRTF-A) -DEFICIENT MICE. IN CULTURED RENAL TUBULAR EPITHELIAL CELLS AND THE KIDNEYS OF MICE WITH DN, MRTF-A WAS INDUCED BY GLUCOSE AND SYNERGIZED WITH GLUCOSE TO ACTIVATE COLLAGEN TRANSCRIPTION. NOTABLY, MRTF-A SILENCING LED TO THE DISAPPEARANCE OF PROMINENT HISTONE MODIFICATIONS INDICATIVE OF TRANSCRIPTIONAL ACTIVATION, INCLUDING ACETYLATED HISTONE H3K18/K27 AND TRIMETHYLATED HISTONE H3K4. DETAILED ANALYSIS REVEALED THAT MRTF-A RECRUITED P300, A HISTONE ACETYLTRANSFERASE, AND WD REPEAT-CONTAINING PROTEIN 5 (WDR5), A KEY COMPONENT OF THE HISTONE H3K4 METHYLTRANSFERASE COMPLEX, TO THE COLLAGEN PROMOTERS AND ENGAGED THESE PROTEINS IN TRANSCRIPTIONAL ACTIVATION. ESTRADIOL SUPPRESSED COLLAGEN PRODUCTION BY DAMPENING THE EXPRESSION AND BINDING ACTIVITY OF MRTF-A AND INTERFERING WITH THE INTERACTION BETWEEN P300 AND WDR5 IN RENAL EPITHELIAL CELLS. THEREFORE, TARGETING THE MRTF-A-ASSOCIATED EPIGENETIC MACHINERY MIGHT YIELD INTERVENTIONAL STRATEGIES AGAINST DN-ASSOCIATED RENAL FIBROSIS. 2015 10 2117 29 EPIGENETIC HISTONE METHYLATION MODULATES FIBROTIC GENE EXPRESSION. TGF-BETA1-INDUCED EXPRESSION OF EXTRACELLULAR MATRIX (ECM) GENES PLAYS A MAJOR ROLE IN THE DEVELOPMENT OF CHRONIC RENAL DISEASES SUCH AS DIABETIC NEPHROPATHY. ALTHOUGH MANY KEY TRANSCRIPTION FACTORS ARE KNOWN, MECHANISMS INVOLVING THE NUCLEAR CHROMATIN THAT MODULATE ECM GENE EXPRESSION REMAIN UNCLEAR. HERE, WE EXAMINED THE ROLE OF EPIGENETIC CHROMATIN MARKS SUCH AS HISTONE H3 LYSINE METHYLATION (H3KME) IN TGF-BETA1-INDUCED GENE EXPRESSION IN RAT MESANGIAL CELLS UNDER NORMAL AND HIGH-GLUCOSE (HG) CONDITIONS. TGF-BETA1 INCREASED THE EXPRESSION OF THE ECM-ASSOCIATED GENES CONNECTIVE TISSUE GROWTH FACTOR, COLLAGEN-ALPHA1[IOTA], AND PLASMINOGEN ACTIVATOR INHIBITOR-1. INCREASED LEVELS OF CHROMATIN MARKS ASSOCIATED WITH ACTIVE GENES (H3K4ME1, H3K4ME2, AND H3K4ME3), AND DECREASED LEVELS OF REPRESSIVE MARKS (H3K9ME2 AND H3K9ME3) AT THESE GENE PROMOTERS ACCOMPANIED THESE CHANGES IN EXPRESSION. TGF-BETA1 ALSO INCREASED EXPRESSION OF THE H3K4 METHYLTRANSFERASE SET7/9 AND RECRUITMENT TO THESE PROMOTERS. SET7/9 GENE SILENCING WITH SIRNAS SIGNIFICANTLY ATTENUATED TGF-BETA1-INDUCED ECM GENE EXPRESSION. FURTHERMORE, A TGF-BETA1 ANTIBODY NOT ONLY BLOCKED HG-INDUCED ECM GENE EXPRESSION BUT ALSO REVERSED HG-INDUCED CHANGES IN PROMOTER H3KME LEVELS AND SET7/9 OCCUPANCY. TAKEN TOGETHER, THESE RESULTS SHOW THE FUNCTIONAL ROLE OF EPIGENETIC CHROMATIN HISTONE H3KME IN TGF-BETA1-MEDIATED ECM GENE EXPRESSION IN MESANGIAL CELLS UNDER NORMAL AND HG CONDITIONS. PHARMACOLOGIC AND OTHER THERAPIES THAT REVERSE THESE MODIFICATIONS COULD HAVE POTENTIAL RENOPROTECTIVE EFFECTS FOR DIABETIC NEPHROPATHY. 2010 11 3357 28 HISTONE H3 LYSINE 9 DI-METHYLATION AS AN EPIGENETIC SIGNATURE OF THE INTERFERON RESPONSE. EFFECTIVE ANTIVIRAL IMMUNITY DEPENDS ON THE ABILITY OF INFECTED CELLS OR CELLS TRIGGERED WITH VIRUS-DERIVED NUCLEIC ACIDS TO PRODUCE TYPE I INTERFERON (IFN), WHICH ACTIVATES TRANSCRIPTION OF NUMEROUS ANTIVIRAL GENES. HOWEVER, DISPROPORTIONATELY STRONG OR CHRONIC IFN EXPRESSION IS A COMMON CAUSE OF INFLAMMATORY AND AUTOIMMUNE DISEASES. WE DESCRIBE AN EPIGENETIC MECHANISM THAT DETERMINES CELL TYPE-SPECIFIC DIFFERENCES IN IFN AND IFN-STIMULATED GENE (ISG) EXPRESSION IN RESPONSE TO EXOGENOUS SIGNALS. WE IDENTIFY DI-METHYLATION OF HISTONE H3 AT LYSINE 9 (H3K9ME2) AS A SUPPRESSOR OF IFN AND IFN-INDUCIBLE ANTIVIRAL GENE EXPRESSION. WE SHOW THAT LEVELS OF H3K9ME2 AT IFN AND ISG CORRELATE INVERSELY WITH THE SCOPE AND AMPLITUDE OF IFN AND ISG EXPRESSION IN FIBROBLASTS AND DENDRITIC CELLS. ACCORDINGLY, GENETIC ABLATION OR PHARMACOLOGICAL INACTIVATION OF LYSINE METHYLTRANSFERASE G9A, WHICH IS ESSENTIAL FOR THE GENERATION OF H3K9ME2, RESULTED IN PHENOTYPIC CONVERSION OF FIBROBLASTS INTO HIGHLY POTENT IFN-PRODUCING CELLS AND RENDERED THESE CELLS RESISTANT TO PATHOGENIC RNA VIRUSES. IN SUMMARY, OUR STUDIES IMPLICATE H3K9ME2 AND ENZYMES CONTROLLING ITS ABUNDANCE AS KEY REGULATORS OF INNATE ANTIVIRAL IMMUNITY. 2012 12 1654 25 DORSAL ROOT GANGLIA COACTIVATOR-ASSOCIATED ARGININE METHYLTRANSFERASE 1 CONTRIBUTES TO PERIPHERAL NERVE INJURY-INDUCED PAIN HYPERSENSITIVITIES. NEUROPATHIC PAIN IS ASSOCIATED WITH GENE EXPRESSION CHANGES WITHIN THE DORSAL ROOT GANGLION (DRG) AFTER PERIPHERAL NERVE INJURY, WHICH INVOLVES EPIGENETIC MECHANISMS. COACTIVATOR-ASSOCIATED ARGININE METHYLTRANSFERASE 1 (CARM1), AN EPIGENETIC ACTIVATOR, REGULATES GENE TRANSCRIPTIONAL ACTIVITY BY PROTEIN POSTTRANSLATIONAL MODIFICATIONS. HOWEVER, WHETHER CARM1 PLAYS AN ESSENTIAL ROLE IN THE DEVELOPMENT AND MAINTENANCE OF NEUROPATHIC PAIN IS UNKNOWN. WE REPORT HERE THAT PERIPHERAL NERVE INJURY INDUCED THE UPREGULATION OF THE MRNA AND PROTEIN EXPRESSION OF CARM1 IN THE INJURED DRG, AND BLOCKING ITS EXPRESSION THROUGH SMALL INTERFERING RNA (SIRNA) IN THE INJURED DRG ATTENUATED THE DEVELOPMENT AND MAINTENANCE OF NEUROPATHIC PAIN. FURTHERMORE, PHARMACOLOGICAL INHIBITION OF CARM1 MITIGATED PERIPHERAL NERVE INJURY-INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA. GIVEN THAT CARM1 INHIBITION OR KNOCKDOWN ATTENUATED THE INDUCTION AND MAINTENANCE OF NEUROPATHIC PAIN AFTER PERIPHERAL NERVE INJURY, OUR FINDINGS SUGGEST THAT CARM1 MAY SERVE AS A PROMISING THERAPEUTIC TARGET FOR NEUROPATHIC PAIN TREATMENT IN CLINICAL APPLICATIONS. 2018 13 3191 35 HDAC AND HAT INHIBITORS DIFFERENTLY AFFECT ANALGESIA MEDIATED BY GROUP II METABOTROPIC GLUTAMATE RECEPTORS. BACKGROUND: HISTONE DEACETYLASES (HDACS) AND HISTONE ACETYLTRANSFERASES (HATS) ARE KEY PLAYERS IN EPIGENETIC REGULATION OF GENE EXPRESSION. ANALGESIC ACTIVITY BY HDAC INHIBITORS HAS BEEN REPORTED IN DIFFERENT PAIN MODELS INCLUDING INFLAMMATORY AND NEUROPATHIC PAIN. THESE DRUGS INTERFERE WITH GENE EXPRESSION THROUGH DIFFERENT MECHANISMS INCLUDING CHROMATIN REMODELING AND/OR ACTIVATION OF TRANSCRIPTION FACTORS. AMONG OTHER TARGETS, HDAC INHIBITORS REGULATE METABOTROPIC GLUTAMATE RECEPTORS TYPE 2 (MGLU2) EXPRESSION IN CENTRAL AND PERIPHERAL CENTRAL NERVOUS SYSTEM. HOWEVER WHETHER INHIBITION OF HAT ACTIVITY ALSO REGULATES MGLU2 EXPRESSION HAS NOT BEEN REPORTED. FINDINGS: HERE WE REPORT THAT CURCUMIN (CUR), A NATURALLY OCCURRING COMPOUND ENDOWED WITH P300/CREB-BINDING PROTEIN HAT INHIBITORY ACTIVITY, IS ABLE TO INDUCE A DRASTIC DOWN-REGULATION OF THE MGLU2 RECEPTOR IN THE MOUSE SPINAL CORD AFTER SYSTEMIC ADMINISTRATION TOGETHER WITH A MARKED HYPOACETYLATION OF HISTONES H3 AND H4 IN DORSAL ROOT GANGLIA (DRG). FURTHERMORE, THE ANALGESIC ACTIVITY OF THE MGLU2/3 AGONIST, LY379268 IS LOST AFTER A 3-DAY TREATMENT WITH CUR. CONVERSELY THE ANALGESIC ACTIVITY OF LY379268 IS POTENTIATED IN MICE PRETREATED FOR 5 CONSECUTIVE DAYS WITH THE HDAC INHIBITOR, SUBEROYLANILIDE HYDROXAMIC ACID (SAHA), KNOWN TO INDUCE MGLU2-UPREGULATION. CONCLUSIONS: OUR RESULTS DEMONSTRATE THAT SYSTEMICALLY INJECTED CUR IS ABLE TO INHIBIT H3 AND H4 ACETYLATION IN THE DRG AND TO DOWN-REGULATE MGLU2 RECEPTORS IN THE SPINAL CORD. WE ALSO DEMONSTRATE THAT LONG TERM MODIFICATION OF THE MGLU2 EXPRESSION AFFECTS THE ANALGESIC PROPERTIES OF THE ORTHOSTERIC MGLU2/3 AGONIST, LY379268. THESE DATA OPEN UP THE POSSIBILITY THAT EPIGENETIC MODULATORS MIGHT BE GIVEN IN COMBINATION WITH "TRADITIONAL" DRUGS IN A CONTEXT OF A MULTI TARGET APPROACH FOR A BETTER ANALGESIC EFFICACY. 2014 14 5995 27 TGFBETA-INDUCED FIBROBLAST ACTIVATION REQUIRES PERSISTENT AND TARGETED HDAC-MEDIATED GENE REPRESSION. TISSUE FIBROSIS IS A CHRONIC DISEASE DRIVEN BY PERSISTENT FIBROBLAST ACTIVATION THAT HAS RECENTLY BEEN LINKED TO EPIGENETIC MODIFICATIONS. HERE, WE SCREENED A SMALL LIBRARY OF EPIGENETIC SMALL-MOLECULE MODULATORS TO IDENTIFY COMPOUNDS CAPABLE OF INHIBITING OR REVERSING TGFBETA-MEDIATED FIBROBLAST ACTIVATION. WE IDENTIFIED PRACINOSTAT, AN HDAC INHIBITOR, AS A POTENT ATTENUATOR OF LUNG FIBROBLAST ACTIVATION AND CONFIRMED ITS EFFICACY IN PATIENT-DERIVED FIBROBLASTS ISOLATED FROM FIBROTIC LUNG TISSUE. MECHANISTICALLY, WE FOUND THAT HDAC-DEPENDENT TRANSCRIPTIONAL REPRESSION WAS AN EARLY AND ESSENTIAL EVENT IN TGFBETA-MEDIATED FIBROBLAST ACTIVATION. TREATMENT OF LUNG FIBROBLASTS WITH PRACINOSTAT BROADLY ATTENUATED TGFBETA-MEDIATED EPIGENETIC REPRESSION AND PROMOTED FIBROBLAST QUIESCENCE. WE CONFIRMED A SPECIFIC ROLE FOR HDAC-DEPENDENT HISTONE DEACETYLATION IN THE PROMOTER REGION OF THE ANTI-FIBROTIC GENE PPARGC1A (PGC1ALPHA) IN RESPONSE TO TGFBETA STIMULATION. FINALLY, WE IDENTIFIED HDAC7 AS A KEY FACTOR WHOSE SIRNA-MEDIATED KNOCKDOWN ATTENUATES FIBROBLAST ACTIVATION WITHOUT ALTERING GLOBAL HISTONE ACETYLATION. TOGETHER, THESE RESULTS PROVIDE NOVEL MECHANISTIC INSIGHT INTO THE ESSENTIAL ROLE HDACS PLAY IN TGFBETA-MEDIATED FIBROBLAST ACTIVATION VIA TARGETED GENE REPRESSION. 2019 15 199 26 ACTIVATED HISTONE ACETYLTRANSFERASE P300/CBP-RELATED SIGNALLING PATHWAYS MEDIATE UP-REGULATION OF NADPH OXIDASE, INFLAMMATION, AND FIBROSIS IN DIABETIC KIDNEY. ACCUMULATING EVIDENCE IMPLICATES THE HISTONE ACETYLATION-BASED EPIGENETIC MECHANISMS IN THE PATHOETIOLOGY OF DIABETES-ASSOCIATED MICRO-/MACROVASCULAR COMPLICATIONS. DIABETIC KIDNEY DISEASE (DKD) IS A PROGRESSIVE CHRONIC INFLAMMATORY MICROVASCULAR DISORDER ULTIMATELY LEADING TO GLOMERULOSCLEROSIS AND KIDNEY FAILURE. WE HYPOTHESIZED THAT HISTONE ACETYLTRANSFERASE P300/CBP MAY BE INVOLVED IN MEDIATING DIABETES-ACCELERATED RENAL DAMAGE. IN THIS STUDY, WE AIMED AT INVESTIGATING THE POTENTIAL ROLE OF P300/CBP IN THE UP-REGULATION OF RENAL NADPH OXIDASE (NOX), REACTIVE OXYGEN SPECIES (ROS) PRODUCTION, INFLAMMATION, AND FIBROSIS IN DIABETIC MICE. DIABETIC C57BL/6J MICE WERE RANDOMIZED TO RECEIVE 10 MG/KG C646, A SELECTIVE P300/CBP INHIBITOR, OR ITS VEHICLE FOR 4 WEEKS. WE FOUND THAT IN THE KIDNEY OF C646-TREATED DIABETIC MICE, THE LEVEL OF H3K27AC, AN EPIGENETIC MARK OF ACTIVE GENE EXPRESSION, WAS SIGNIFICANTLY REDUCED. PHARMACOLOGICAL INHIBITION OF P300/CBP SIGNIFICANTLY DOWN-REGULATED THE DIABETES-INDUCED ENHANCED EXPRESSION OF NOX SUBTYPES, PRO-INFLAMMATORY, AND PRO-FIBROTIC MOLECULES IN THE KIDNEY OF MICE, AND THE GLOMERULAR ROS OVERPRODUCTION. OUR STUDY PROVIDES EVIDENCE THAT THE ACTIVATION OF P300/CBP ENHANCES ROS PRODUCTION, POTENTIALLY GENERATED BY UP-REGULATED NOX, INFLAMMATION, AND THE PRODUCTION OF EXTRACELLULAR MATRIX PROTEINS IN THE DIABETIC KIDNEY. THE DATA SUGGEST THAT P300/CBP-PHARMACOLOGICAL INHIBITORS MAY BE ATTRACTIVE TOOLS TO MODULATE DIABETES-ASSOCIATED PATHOLOGICAL PROCESSES TO EFFICIENTLY REDUCE THE BURDEN OF DKD. 2021 16 2425 19 EPIGENETIC SILENCING OF IRF1 DYSREGULATES TYPE III INTERFERON RESPONSES TO RESPIRATORY VIRUS INFECTION IN EPITHELIAL TO MESENCHYMAL TRANSITION. CHRONIC OXIDATIVE INJURY PRODUCED BY AIRWAY DISEASE TRIGGERS A TRANSFORMING GROWTH FACTOR-BETA (TGF-BETA)-MEDIATED EPIGENETIC REPROGRAMMING KNOWN AS THE EPITHELIAL-MESENCHYMAL TRANSITION (EMT). WE OBSERVE THAT EMT SILENCES PROTECTIVE MUCOSAL INTERFERON (IFN)-I AND III PRODUCTION ASSOCIATED WITH ENHANCED RHINOVIRUS (RV) AND RESPIRATORY SYNCYTIAL VIRUS (RSV) REPLICATION. MESENCHYMAL TRANSITIONED CELLS ARE DEFECTIVE IN INDUCIBLE INTERFERON REGULATORY FACTOR 1 (IRF1) EXPRESSION BY OCCLUDING RELA AND IRF3 ACCESS TO THE PROMOTER. IRF1 IS NECESSARY FOR THE EXPRESSION OF TYPE III IFNS (IFNLS 1 AND 2/3). INDUCED BY THE EMT, ZINC FINGER E-BOX BINDING HOMEOBOX 1 (ZEB1) BINDS AND SILENCES IRF1. ECTOPIC ZEB1 IS SUFFICIENT FOR IRF1 SILENCING, WHEREAS ZEB1 KNOCKDOWN PARTIALLY RESTORES IRF1-IFNL UPREGULATION. ZEB1 SILENCES IRF1 THROUGH THE CATALYTIC ACTIVITY OF THE ENHANCER OF ZESTE 2 POLYCOMB REPRESSIVE COMPLEX 2 SUBUNIT (EZH2), FORMING REPRESSIVE H3K27(ME3) MARKS. WE OBSERVE THAT IRF1 EXPRESSION IS MEDIATED BY ZEB1 DE-REPRESSION, AND OUR STUDY DEMONSTRATES HOW AIRWAY REMODELLING/FIBROSIS IS ASSOCIATED WITH A DEFECTIVE MUCOSAL ANTIVIRAL RESPONSE THROUGH ZEB1-INITIATED EPIGENETIC SILENCING. 2017 17 6767 27 ZNF382 CONTROLS MOUSE NEUROPATHIC PAIN VIA SILENCER-BASED EPIGENETIC INHIBITION OF CXCL13 IN DRG NEURONS. NERVE INJURY-INDUCED CHANGES OF GENE EXPRESSION IN DORSAL ROOT GANGLION (DRG) ARE CRITICAL FOR NEUROPATHIC PAIN GENESIS. HOWEVER, HOW THESE CHANGES OCCUR REMAINS ELUSIVE. HERE WE REPORT THE DOWN-REGULATION OF ZINC FINGER PROTEIN 382 (ZNF382) IN INJURED DRG NEURONS AFTER NERVE INJURY. RESCUING THIS DOWN-REGULATION ATTENUATES NOCICEPTIVE HYPERSENSITIVITY. CONVERSELY, MIMICKING THIS DOWN-REGULATION PRODUCES NEUROPATHIC PAIN SYMPTOMS, WHICH ARE ALLEVIATED BY C-X-C MOTIF CHEMOKINE 13 (CXCL13) KNOCKDOWN OR ITS RECEPTOR CXCR5 KNOCKOUT. MECHANISTICALLY, AN IDENTIFIED CIS-ACTING SILENCER AT DISTAL UPSTREAM OF THE CXCL13 PROMOTER SUPPRESSES CXCL13 TRANSCRIPTION VIA BINDING TO ZNF382. BLOCKING THIS BINDING OR GENETICALLY DELETING THIS SILENCER ABOLISHES THE ZNF382 SUPPRESSION ON CXCL13 TRANSCRIPTION AND IMPAIRS ZNF382-INDUCED ANTINOCICEPTION. MOREOVER, ZNF382 DOWN-REGULATION DISRUPTS THE REPRESSIVE EPIGENETIC COMPLEX CONTAINING HISTONE DEACETYLASE 1 AND SET DOMAIN BIFURCATED 1 AT THE SILENCER-PROMOTER LOOP, RESULTING IN CXCL13 TRANSCRIPTIONAL ACTIVATION. THUS, ZNF382 DOWN-REGULATION IS REQUIRED FOR NEUROPATHIC PAIN LIKELY THROUGH SILENCER-BASED EPIGENETIC DISINHIBITION OF CXCL13, A KEY NEUROPATHIC PAIN PLAYER, IN DRG NEURONS. 2021 18 4906 29 P300 EXERTS AN EPIGENETIC ROLE IN CHRONIC NEUROPATHIC PAIN THROUGH ITS ACETYLTRANSFERASE ACTIVITY IN RATS FOLLOWING CHRONIC CONSTRICTION INJURY (CCI). BACKGROUND: NEUROPATHIC PAIN IS DETRIMENTAL TO HUMAN HEALTH; HOWEVER, ITS PATHOGENESIS STILL REMAINS LARGELY UNKNOWN. OVEREXPRESSION OF PAIN-ASSOCIATED GENES AND INCREASED NOCICEPTIVE SOMATO-SENSITIVITY ARE WELL OBSERVED IN NEUROPATHIC PAIN. THE IMPORTANCE OF EPIGENETIC MECHANISMS IN REGULATING THE EXPRESSION OF PRO- OR ANTI-NOCICEPTIVE GENES HAS BEEN REVEALED BY STUDIES RECENTLY, AND WE HYPOTHESIZE THAT THE TRANSCRIPTIONAL COACTIVATOR AND THE HISTONE ACETYLTRANSFERASE E1A BINDING PROTEIN P300 (P300), AS A PART OF THE EPIGENETIC MECHANISMS OF GENE REGULATION, MAY BE INVOLVED IN THE PATHOGENESIS OF NEUROPATHIC PAIN INDUCED BY CHRONIC CONSTRICTION INJURY (CCI). TO TEST THIS HYPOTHESIS, TWO DIFFERENT APPROACHES WERE USED IN THIS STUDY: (I) DOWN-REGULATING P300 WITH SPECIFIC SMALL HAIRPIN RNA (SHRNA) AND (II) CHEMICAL INHIBITION OF P300 ACETYLTRANSFERASE ACTIVITY BY A SMALL MOLECULE INHIBITOR, C646. RESULTS: USING THE CCI RAT MODEL, WE FOUND THAT THE P300 EXPRESSION WAS INCREASED IN THE LUMBAR SPINAL CORD ON DAY 14 AFTER CCI. THE TREATMENT WITH INTRATHECAL P300 SHRNA REVERSED CCI-INDUCED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA, AND SUPPRESSED THE EXPRESSION OF CYCLOOXYGENASE-2 (COX-2), A NEUROPATHIC PAIN-ASSOCIATED FACTOR. FURTHERMORE, C646, AN INHIBITOR OF P300 ACETYLTRANSFERASE, ALSO ATTENUATED MECHANICAL ALLODYNIA AND THERMAL HYPERALGESIA, ACCOMPANIED BY A SUPPRESSED COX-2 EXPRESSION, IN THE SPINAL CORD. CONCLUSIONS: THE RESULTS SUGGEST THAT, THROUGH ITS ACETYLTRANSFERASE ACTIVITY IN THE SPINAL CORD AFTER CCI, P300 EPIGENETICALLY PLAYS AN IMPORTANT ROLE IN NEUROPATHIC PAIN. INHIBITING P300, USING INTERFERING RNA OR C646, MAY BE A PROMISING APPROACH TO THE DEVELOPMENT OF NEW NEUROPATHIC PAIN THERAPIES. 2012 19 2885 23 G9A PARTICIPATES IN NERVE INJURY-INDUCED KCNA2 DOWNREGULATION IN PRIMARY SENSORY NEURONS. NERVE INJURY-INDUCED DOWNREGULATION OF VOLTAGE-GATED POTASSIUM CHANNEL SUBUNIT KCNA2 IN THE DORSAL ROOT GANGLION (DRG) IS CRITICAL FOR DRG NEURONAL EXCITABILITY AND NEUROPATHIC PAIN GENESIS. HOWEVER, HOW NERVE INJURY CAUSES THIS DOWNREGULATION IS STILL ELUSIVE. EUCHROMATIC HISTONE-LYSINE N-METHYLTRANSFERASE 2, ALSO KNOWN AS G9A, METHYLATES HISTONE H3 ON LYSINE RESIDUE 9 TO PREDOMINANTLY PRODUCE A DYNAMIC HISTONE DIMETHYLATION, RESULTING IN CONDENSED CHROMATIN AND GENE TRANSCRIPTIONAL REPRESSION. WE SHOWED HERE THAT BLOCKING NERVE INJURY-INDUCED INCREASE IN G9A RESCUED KCNA2 MRNA AND PROTEIN EXPRESSION IN THE AXOTOMIZED DRG AND ATTENUATED THE DEVELOPMENT OF NERVE INJURY-INDUCED PAIN HYPERSENSITIVITY. MIMICKING THIS INCREASE DECREASED KCNA2 MRNA AND PROTEIN EXPRESSION, REDUCED KV CURRENT, AND INCREASED EXCITABILITY IN THE DRG NEURONS AND LED TO SPINAL CORD CENTRAL SENSITIZATION AND NEUROPATHIC PAIN-LIKE SYMPTOMS. G9A MRNA IS CO-LOCALIZED WITH KCNA2 MRNA IN THE DRG NEURONS. THESE FINDINGS INDICATE THAT G9A CONTRIBUTES TO NEUROPATHIC PAIN DEVELOPMENT THROUGH EPIGENETIC SILENCING OF KCNA2 IN THE AXOTOMIZED DRG. 2016 20 4615 26 NERVE INJURY DIMINISHES OPIOID ANALGESIA THROUGH LYSINE METHYLTRANSFERASE-MEDIATED TRANSCRIPTIONAL REPRESSION OF MU-OPIOID RECEPTORS IN PRIMARY SENSORY NEURONS. THE MU-OPIOID RECEPTOR (MOR, ENCODED BY OPRM1) AGONISTS ARE THE MAINSTAY ANALGESICS FOR TREATING MODERATE TO SEVERE PAIN. NERVE INJURY CAUSES DOWN-REGULATION OF MORS IN THE DORSAL ROOT GANGLION (DRG) AND DIMINISHES THE OPIOID EFFECT ON NEUROPATHIC PAIN. HOWEVER, THE EPIGENETIC MECHANISMS UNDERLYING THE DIMINISHED MOR EXPRESSION CAUSED BY NERVE INJURY ARE NOT CLEAR. G9A (ENCODED BY EHMT2), A HISTONE 3 AT LYSINE 9 METHYLTRANSFERASE, IS A KEY CHROMATIN REGULATOR RESPONSIBLE FOR GENE SILENCING. IN THIS STUDY, WE DETERMINED THE ROLE OF G9A IN DIMINISHED MOR EXPRESSION AND OPIOID ANALGESIC EFFECTS IN ANIMAL MODELS OF NEUROPATHIC PAIN. WE FOUND THAT NERVE INJURY IN RATS INDUCED A LONG-LASTING REDUCTION IN THE EXPRESSION LEVEL OF MORS IN THE DRG BUT NOT IN THE SPINAL CORD. NERVE INJURY CONSISTENTLY INCREASED THE ENRICHMENT OF THE G9A PRODUCT HISTONE 3 AT LYSINE 9 DIMETHYLATION IN THE PROMOTER OF OPRM1 IN THE DRG. G9A INHIBITION OR SIRNA KNOCKDOWN FULLY REVERSED MOR EXPRESSION IN THE INJURED DRG AND POTENTIATED THE MORPHINE EFFECT ON PAIN HYPERSENSITIVITY INDUCED BY NERVE INJURY. IN MICE LACKING EHMT2 IN DRG NEURONS, NERVE INJURY FAILED TO REDUCE THE EXPRESSION LEVEL OF MORS AND THE MORPHINE EFFECT. IN ADDITION, G9A INHIBITION OR EHMT2 KNOCKOUT IN DRG NEURONS NORMALIZED NERVE INJURY-INDUCED REDUCTION IN THE INHIBITORY EFFECT OF THE OPIOID ON SYNAPTIC GLUTAMATE RELEASE FROM PRIMARY AFFERENT NERVES. OUR FINDINGS INDICATE THAT G9A CONTRIBUTES CRITICALLY TO TRANSCRIPTIONAL REPRESSION OF MORS IN PRIMARY SENSORY NEURONS IN NEUROPATHIC PAIN. G9A INHIBITORS MAY BE USED TO ENHANCE THE OPIOID ANALGESIC EFFECT IN THE TREATMENT OF CHRONIC NEUROPATHIC PAIN. 2016